Thực hiện phép tính
a) \(\left(\sqrt{ab}+2\sqrt{\frac{b}{a}}-\sqrt{\frac{a}{b}+\sqrt{\frac{1}{ab}}}\right).\sqrt{ab}\)
b) \(\left(\frac{am}{b}\sqrt{\frac{n}{m}}-\frac{ab}{n}\sqrt{mn}+\frac{a^2}{b^2}\sqrt{\frac{m}{n}}\right).a^2b^2.\sqrt{\frac{n}{m}}\)